Essentially a centrifuge is an apparatus that separates differing density constituents that are in a fluid. Centrifugation provides a means for achieving two goals through one approach: differing density constituents can be both concentrated and purified under centrifugal forces. Centrifugation causes the heavier particles or constituents to sediment rapidly in the direction outward from the center of rotation. The centrifugal force generated by centrifugation is proportional to the speed of rotation and the radius of the rotor. Gee force is the force acting on a body as a result of acceleration or gravity. At a fixed centrifugal force and medium viscosity, the sedimentation rate of the particle is proportional to the molecular weight of the particle and the difference between its density and the density of the medium. This observation has led to the use red cell aggregating agents such as HESPAN™ (hydroxyl-ethyl starch) to enhance the differential stratification of red cells from leukocytes by centrifugation. The use of this type of sedimentation agent is applicable to the present invention.
The principles of centrifugation for cell separation have been reviewed in a U.S. patent application of Chapman and Sparks entitled “Centrifuge and Separation Vessel Therefore” having application Ser. No. 13/199,111 and published as Publication No. 2012/0065047 on Mar. 12, 2012, the entire contents of which are incorporated herein by reference.
Centrifuges are suited and used for the separation of components including cells, organelles or macromolecules contained in biologic fluids including bone marrow, peripheral blood, urine, phlegm, synovial semen, milk, saliva, mucus, sputum, exudates, cerebrospinal fluid, amniotic fluid, cord blood, intestinal fluid, cell suspensions, tissue digests, tumor cell containing cell suspensions, microbe containing cell suspensions, radio-labeled cell suspensions and cell culture fluid for therapeutic or diagnostic purposes.
Centrifuges are well suited for the washing of cell suspensions and other particulate matter. Centrifuges also are used for separation of components present in aqueous solutions, lake water, ocean water, river water, waste water, and sewage for the purpose of preparative analytical testing or purification. Centrifuges are also suited for the separation of a component of an inorganic or organic chemical reaction that has resulted in the formation of a precipitate or flocculent. Centrifuges are employed in industrial applications including manufacturing and purification in food and beverages, in metallurgy, mining of precious metals including gold, silver and platinum. Centrifuges have been used for separation of particulates added to an aqueous solution for the purpose of inducing a chemical reaction and then terminating said chemical reaction by centrifugation of the heterogeneous fluid using the apparatus of the invention. Centrifuges have been used to in combination with density particles to perform immunoaffinity cell separation steps which is also applicable to the present invention. This expansive list is still not inclusive for all the varied functions for which centrifuges are routinely employed and are applicable to the present invention. Detailed examples of centrifuge vessels employed in these applications are summarized in U.S. Provisional Application No. 61/401,877 filed on Aug. 21, 2010, the entire contents of which are hereby incorporated herein by reference.
The present invention in some of its embodiments also relates to the field of medical suction canisters and more particularly to a suction canister assembly designed for the safe collection, centrifugal separation of body fluids from a patient, harvesting of one or more fractions of the separated lipoaspirate for use in therapeutic or cosmetic applications.
During the course of a surgical operation on a patient, it is often necessary to remove from the site of the operation various body fluids including blood, tissue fragments, and other viscid fluids which tend to collect at the operation site. Removal of such body fluids is generally accomplished using an aspirator connected to a source of vacuum to draw the fluids through a suitable tube for deposit into a collection bottle or canister. Body fluid storage canisters for use in such systems are well known in the art. Typically, such canister assemblies include a canister and cover which are secured together with a leak tight seal. Two connections are provided in the cover, a vacuum port for being connected by a tube or other suitable connections to a source of vacuum, for example, a vacuum pump or hospital vacuum outlet station. The other connection comprises a fluid receiving port which is connected through a drainage tube to the surgical operating site on a patient. In the suction canister, a vacuum is produced to create a vacuum in the tube leading to the operation site from which fluids are to be withdrawn. This vacuum carries the fluid through the drainage tube to an inlet in the suction canister enabling complete or partial filling of the canister.
Vacuum aspiration has become popular in several surgical procedures including fat liposuctions. Among the most common liposuctions are typically accomplished by inserting the distal end of a narrow metal cannula through a small incision in the skin and applying a vacuum suction, generally through a hose attached to the proximal end of the cannula. Liposuction cannulas generally consist of a hollow handle in which the shaft of the cannula is inserted. Various tip and hole configurations through which fat is suctioned are situated at the distal end of the cannula. After inserting the distal end of the cannula through the incision in the skin, the surgeon carefully moves the cannula forward and backward within the layer of fat. This movement shears off fat tissue particles, which are drawn into the cannula and out of the body by the vacuum. The hose leads to a suction canister, which is designed to hold the adipose tissue and its fluid constituents.
In U.S. Pat. No. 5,786,207 to Katz et al., issued Jul. 28, 1998, the entire contents of which are incorporated herein by reference, discloses a device for dissociating tissue into a single cell suspension. The problems identified by Katz and Lull for processing lipoaspirate included the viscosity of the tissue sample being further increased by the oil released from cells damaged during the liposuction procedure or cell separation process. They also noted lipoaspirate having a thick, slurry-like consistency which is caused by oil, serum, tissue fragments and other fluids. They further noted the consistency of such liposuctioned tissue, particularly large samples of such tissue, causes occlusion of filtering mechanisms and is a significant hindrance to thorough, effective washing and cell separation.
Suction canisters are known for floor, cabinet and wall mounting, generally for medical uses to provide suction at a patient bedside for various purposes such as wound cleansing, sanitation purposes, aspiration and the like. The canister includes a plastic or glass container which can be of different sizes onto which a plastic lid is fitted. The lid is formed with tubular fittings or ports connectable to a suction inlet hose and a patient outlet hose.
Said suction canister are known in the prior art to be hard suction canister wherein the walls of the vessel are sufficiently strong to within stand implosion as a result of the vacuum force applied and also to be construction of single use disposable suction canister liners which are housed in reusable hard canister to provide support for the suction canister during the lipoaspiration procedure.
It is known in the prior art to have lids of hard suction canister or lids of suction canister liners to include a one-way valve built into the inner lid at the patient port to prevent back flow of fluid into the tubing connected to the cannula.
An automatic shutoff valve is known in the prior art to be located inside the lid of a hard suction canister or the lid of a suction canister liner to help prevent cross contamination of regulators and wall vacuum outlets. In addition, 90° adapters allow tubing to connect at right angles to help prevent kinking and impeded fluid flow. The use of locking lids has been reported to encourage the proper disposal of infectious liquid medical waste and enhances worker safety. Lid includes accessory and orthopedic ports. The volume of the canister is typically in the range of 100 ml to 3 liters.
The present invention in some of its embodiments relates to cell salvage where cells removed from the body during a surgical procedure are subsequently returned to the body. Prior art systems for salvaging blood from surgical sites and wound drains often employ disposable units that include a reservoir for collecting the blood-containing fluid and a separation device (such as a centrifuge bowl or disk) for separating out and washing the red blood cells (RBCs). The RBCs salvaged using these systems may be auto-transfused back into the patient, thereby reducing the need for allogenic blood transfusions. Examples of such blood-salvage systems include those described in U.S. Pat. No. 6,251,291 to Lamphere et al., issued Jun. 26, 2001, and in U.S. Patent Application Publication No. 2005/0203469 by Bobroff et al., published Sep. 15, 2005 and U.S. Patent Application Publication No. 2008/0108931 by Bobroff published May 8, 2008. Both this patent and published applications are incorporated herein by reference. Blood and other fluids are suctioned from a surgical site and drawn into the reservoir. These fluids are drawn from a reservoir into a centrifuge, which is then spun so as to separate out the red blood cells from the plasma and other fluids. The plasma and other fluids may be directed to a waste bag. The red blood cells may then be washed in the centrifuge disk with saline from the saline source. After washing, the saline may be separated from the RBCs and directed to the waste bag, and the washed red blood cells directed to the red blood cell bag. The red blood cells may then be retransfused into the patient. Often the amount of blood collected in the reservoir is insufficient to carry out the separation and wash procedures. In such a situation, the entire disposable set must be discarded after the procedure. This is wasteful and adds unnecessary expense to surgical procedures that ultimately do not lead to washing and reinfusing of blood to the patient.
The present invention in some of its embodiments relates to the field of cell washing. A particularly important clinical problem is the lack of an effective means to wash away toxic cryopreservative agents present in thawed cell suspensions. DMSO is such a toxic solvent commonly used for the cryopreservation of autologous peripheral blood stem cells, cord blood, and bone marrow. Infusion reactions are expected to occur and include nausea, vomiting, fever, rigors or chills, flushing, dyspnea, hypoxemia, chest tightness, hypertension, tachycardia, bradycardia, dysgeusia, hematuria, and mild headache. Severe reactions, including respiratory distress, severe bronchospasm, severe bradycardia with heart block or other arrhythmias, cardiac arrest, hypotension, hemolysis, elevated liver enzymes, renal compromise, encephalopathy, loss of consciousness, and seizure also may occur. The frequency and severity of these adverse reactions are related to the amount of DMSO administered. Minimizing the amount of DMSO administered may reduce the risk of such reactions, although idiosyncratic responses may occur even at DMSO doses thought to be tolerated. The actual amount of DMSO depends on the method of preparation of the product for infusion. A method for the efficient washing of thawed cryopreserved cells concentrates is therefore a significant unmet need. Other unmet needs for cell washing include removal of enzymes such as collagenase from tissue digests, removal of density media such as Ficoll following density phase separation and removal of lytic reagents after selective cell lysis. It is particularly desirable to have a cell washing system that can be scaled and is simple enough to be used at the point of care when dealing with medical applications.
None of the devices disclosed above adequately address the special processing concerns presented for concentrating viable cells from tissues for medical and veterinary therapeutic applications, diagnostic applications, cosmetic applications wherein simplicity, speed and reliability are highly valued. The ability to conduct cell concentrating, washing, and purification of heterogeneous biological fluids at the intra-operative point of care is particularly important for regenerative medicine and cosmetic surgery applications. Although various vessels for concentrating, washing and purifying biological fluids are documented in the literature, a need exists for a device and method that is more expeditious, efficacious, accessible and practical than current devices and methods. Further, devices do not currently exist that have successfully addressed the technical challenges and operator needs in processing lipoaspirate where the range of volume is high (20 ml to 3 liters) and the fluid is particulate in nature. Therefore, a long held need has existed for a device and method that can enable an operator without special skill and training to prepare volume reduced viable cell concentrates from biological fluids in a practical and reliable manner. What is needed is a single device that enables both the collection of the lipoaspirate and its separation by centrifugation into phase components based upon density and the means to extract one or more of these density phases for use in therapeutic or cosmetic procedures in a simple and reliable manner.